Known embodiments of vibrating rivet tools and rivet hammers in aircraft construction press the rivet into the rivet hole using considerable mechanical forces acting, in particular, in the axial direction of the rivet. In this case, the rivet tool must apply a force of up to a tonne (approx. 10 kN). Due to the considerable force that is required to press the rivet in, the rivet tools must be configured so as to be correspondingly large and heavy. Rivet machines weighing up to a tonne are therefore required in the case of automated riveting for connecting component.
A more advanced automisation of riveting processes, for example by using conventional industrial articulated arm robots so as to also allow component to be automatically riveted in working positions that are not easily accessible, is thereby impeded.
A device is known from U.S. Pat. No. 5,027,490 for inserting rivets into superimposed workpieces. The complex and heavy device comprises, inter alia, a drive unit and a vibration unit. A static force for pressing the rivets is first applied by way of a drive unit whilst the vibration unit reduces mechanical stresses in the workpieces after the rivets have actually been fixed in position.
DE 197 29 368 A1 also relates to a device and a method for mechanically joining sheet metal plates, profiles and/or multiple-sheet metal connections. In the case of this rivet device, the rivet is driven into the workpieces via high-frequency impacts with a relatively low impact energy, the die being resiliently dampingly mounted as an abutment for the tappet. The spring stiffness and/or damping of the die adapt depending on the resonant frequency of the sheet metal plates to be joined. A separate generator for producing high-frequency vibrations is not provided.
A device is further known from U.S. Pat. No. 3,483,611 for joining two component together using force and ultrasound. A first component made, for example, of a textile nylon fabric is disc-shaped, whilst the second component to be connected thereto can be made of metal or plastics material and comprises small prongs, points or spikes pointing upwards. Both components are bonded together in the device similar to a conventional moulding press. The prongs of the lower second component penetrate the upper first component by the simultaneous use of force and ultrasound ranging between 1 kHz and 100 kHz and a vibration amplitude of up to 0.635 mm, the prongs plasticised at least in part by force and ultrasound being reformed so as to be mushroom-shaped. This device does not provide a conventional rivet connection between two sheet metal plates.